Popularity of "The Walking Dead" shows no signs of waning

The Walking Dead," AMC's drama series about a post-apocalyptic world dominated by flesh-eating zombies, appears to have plenty of staying power based on the strong viewership for the show's fourth season.

"We don't know how long it will last," creative director Scott Gimple said at a Screen Actors Guild gathering in Los Angeles that was also attended by Robert Kirkman, creator of the comic book on which the series is based, and two of the show's actors, Lauren Cohan and Steven Yeun.

The comic book series has been published for 11 years, but the television show is a different entity, according to Gimple, who said it would be fun to figure out how to bring it to a conclusion.

Kirkman, for his part, confirmed that he was working on a spinoff series - due to premiere next year on AMC - that is set in the same world but with a parallel storyline about another group of survivors of the zombie apocalypse.

The writer's "Thief of Thieves" comic book series, which tells the story of a master thief who decides to make amends for his past by stealing from other robbers, also is due to be adapted for an AMC television series.

The 35-year-old Kirkman said his life changed when that U.S. basic-cable and satellite-TV channel decided to green-light "The Walking Dead," adding that he never thought the plans for the series would prosper.

The writer said the gory storyline about zombies devouring people's bodies seemed ill-suited for television, but the series has been popular from the outset and seen its viewership numbers increase every season.

A total of 16.11 million viewers in the United States tuned in for the first episode of the fourth season on Oct. 13, 2013, the highest ratings of any episode in the series' history.